Balance weight cartridge with enclosed balance media

ABSTRACT

A balance weight comprising a cartridge having at least one interior chamber, the interior chamber at least partially filled with a flowable balance media, and wherein the cartridge is longitudinally arcuate, at least when attached to a wheel, about an angle of up to 180 degrees or less. The balance weight provides a balanced tire in the new or just balanced condition and helps retain the balance under changes in at least one operational characteristic of the tire/wheel assembly.

This application claims the benefit of U.S. provisional patentapplication Ser. No. 60/488,634, filed Jul. 18, 2003, and is herebyincorporated by reference.

TECHNICAL FIELD

This invention relates to a balance weight for dynamically balancing atire/wheel assembly of a motor vehicle, and more particularly to abalance weight cartridge having an interior chamber at least partiallyfilled with a flowable media which allows for superior balancing underdifferent speeds and changing tire properties.

BACKGROUND OF THE INVENTION

It is standard practice to reduce adverse vibrational effects bybalancing the wheel rim and tire assembly by using a balance machine andclip-on lead weights or lead tape weights. The lead balance weights areplaced on the rim flange of the wheel and clamped in place in a properposition, or adhered to the wheel in the case of tape weights, asdirected by the balancing machine. In general terms, balance is theuniform distribution of mass about an axis of rotation, where the centerof gravity is in the same location as the center of rotation. A balancedtire/wheel assembly is one where mass of the tire/wheel assembly mountedon the vehicle's axle-is uniformly distributed around the axle. Thereare generally two types of balancing, single plane balancing and dualplane balancing. Single plane balancing uses a single weight plane andonly addresses “up-and-down” imbalance. Dual plane balancing uses twoweight planes and thus eliminates “up-and-down” and “side-to-side”imbalance.

While lead weight balancing has been generally effective, there areseveral problems associated with their use. Primarily, the standardwheel weights are manufactured from a lead material that has beenidentified as having a hazardous influence on the environment. Variousnational and multinational regulating agencies have passed rulesrestricting the use of lead balance weights in the future. Balanceweights that are not properly secured may fall off during use—resultingin an unbalanced tire. A further disadvantage is that the standard clipon balance weight is difficult to attach to many of the newer wheelswhich have a reduced wheel flange and are too aesthetically unpleasingto be used on the flanges of fancy alloy wheels. In addition, once thebalance weight is in position, regardless of whether a clip-on or tapeweight, you can no longer adjust to slight to moderate changes in theproper balance location caused by changing tire/wheel assemblyoperational characteristics, i.e. tire wear, different speeds, changesin loads which change the loaded radius of the tire, etc.

Attempts to overcome some of these difficulties in truck tires andwheels have resulted in the development of automatic balancing ringscomprising a 360 degree annular tube filled with weights in combinationwith a damping fluid. The tubes are typically attached adjacent thewheel flange. However, these devices tend to cause out of balanceproblems at lower speeds until the weights are properly positioned. Inaddition, the balancing rings prevent the attachment of wheel covers ordetract from the aesthetics of newer alloy wheels.

The standard wheel balancing systems described above have variousdisadvantages. It would therefore be an advantage to combine thefeatures of the fixed balance weights in a no-lead configuration in amanner that was able to adjust to operational changes in the tire/wheelassembly without the problems associated with balance rings, in a simpleand effective manner.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a balanceweight that will result in a balanced tire in the new or just balancedcondition and to retain the balance under changes in at least oneoperational characteristic of the tire/wheel assembly. These and otheraspects and objects of the invention are provided by a balance weightcomprising a cartridge having an interior chamber at least partiallyfilled with a flowable balance media, wherein the cartridge islongitudinally arcuate, at least when attached to a tire or wheel, aboutan angle of up to 180 degrees or less.

These and other aspects and objects of the invention are also providedby a method of balancing a tire/wheel assembly comprising the steps ofproviding a tire and a wheel; checking the balance condition of the tireand wheel; providing at least one balance weight comprising a cartridgecomprising an interior chamber at least partially filled with a flowablebalance media, wherein the cartridge is longitudinally arcuate, at leastwhen attached to a wheel or a tire, about an angle of upto 180 degreesor less; and attaching the at least one balance weight to one of thetire and wheel such that when the tire is mounted on the wheel, theassembled tire and wheel are balanced.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will now be described in further detail with reference tothe accompanying drawings, in which:

FIG. 1 is an exploded side view of the balance weight of the presentinvention;

FIG. 2 is a longitudinal cross-sectional view of an assembled balanceweight of the present invention;

FIGS. 3A–3C are various perspective views of the cartridge of thepresent invention showing the cross sectional end of the tube andassociated plugs of the present invention;

FIG. 4 is a cross-sectional view of another embodiment of the presentinvention showing a low profile, multi-chamber configuration havingadhesive attachment strips.

FIG. 5 is a perspective view of an embodiment of the present inventionattached to the brake side of the tube well of a tire/wheel assembly;

FIG. 6 is a cross-sectional view of an embodiment of the presentinvention attached to the flange of a tire/wheel assembly;

FIG. 7 is a cross-sectional view of a clip-on embodiment of the presentinvention shown attached to the flange of a tire/wheel assembly;

FIG. 8 is a cross-sectional view of an embodiment of the presentinvention formed integral to a wheel; and

FIG. 9 is a cross-sectional view of an embodiment of the presentinvention formed integral to a tire.

DESCRIPTION OF THE PREFERRED EMBODIMENT

This invention will now be described in detail with reference to variousembodiments thereof. Referring now to FIGS. 1 and 2, an exploded viewand an assembled cross-sectional view, respectively, a first embodimentof the present invention is shown as a balance weight 10 comprising ahollow body or cartridge 20 having a interior chamber 30 at leastpartially filled with a flowable media 40.

The cartridge 20 forms a container and is typically made of a molded orextruded rubber or plastic material that will not react with themetallic surface of a wheel, however the cartridge 20 is not intended tobe limited to such materials and any suitable material such as afabricated aluminum cartridge is also contemplated. The cartridge 20comprises a tube 22 that may be cut or molded to the desired length. Theflowable media 40 is inserted in the tube 22 which is then sealed, mostcommonly with at least one plug 24 or a heat weld seal may also be used.The cartridge 20 may be formed in a rigid longitudinally arcuate sectionof an angle θ equivalent to an angle of one hundred eighty degrees orless, or it may be formed in a flexible straight section and positionedinto an arcuate section of one hundred eighty degrees or less whenattached to a wheel as described in greater detail below. The walls ofthe tube 22 which make up the interior chamber 30 should be of a smoothsurface finish that will promote flow of the flowable media 40.

Some possible variations of the tube 22 used for the cartridge 20 areshown in FIGS. 3A–3C, wherein the cross-section of the tube 22 may beshaped as a “D” and corresponding plug 24 as shown in FIG. 3A or tube22′ may be shaped as a rectangle and corresponding plug 24′ as shown inFIG. 3B. Alternatively, the interior chamber 30 of the tube 22″ may havean oval cross-section and corresponding plug 24″ as shown in FIG. 3C.These embodiments are provided as examples only and are not intended tolimit the scope of the invention to the particular examples shownherein. It is contemplated that any suitable cross-sectional shape maybe used for the tube 22 and interior chamber 30 that does not inhibitthe flow of the flowable material 40. It is also contemplated that thephysical exterior dimension or height of the tube does not interferewith other systems positioned near the tire/wheel assembly such as thebraking system, etc.

Another variation of tube is shown in FIG. 4. Tube 22′″ employs alow-profile configuration which enables the tube 22′″ to be positionedon the inboard side of the wheel without contacting the brakecomponents. Tube 22′″ also provides a relatively large chambercross-sectional area to enable a larger amount of balance media to beused and to allow movement of the media in both a circumferentialdirection as well as a lateral direction to better balance the wheel intwo planes. Adhesive strips 70 are provided on the exterior of tube 22′″to provide means for attaching the tube to the wheel. Tube 22′″ may alsohave more than one chamber 30 as shown in FIG. 4 and designated as 30 aand 30 b. The multiple chambers 30 a, 30 b will help provide structuralrigidity of the chambers 30 a, 30 b by providing an interior wall tosupport the relatively long cross-sectional width or span of tube 22′″.The incorporation of multiple chambers will also limit the lateralmovement of the media between chambers 30 a, 30 b which in someinstances may help the media to better balance the wheel by preventingall of the media from migrating to one side of the tube 22′″ when thewheel well is formed at an angle to the ground.

The flowable material 40 may be metallic balls as best shown in FIGS. 1,2, 5 and 6, preferably stainless-steel, however any suitable flowablematerial is contemplated by the present invention including beads, shot,particles, powders, etc. made of ferrous and non-ferrous metals,ceramics, plastics, glass beads, alumina, etc. It is also contemplatedthat the flowable material may be a liquid, in whole or in part. Suchsuitable materials include any material that is stable and remains freeflowing over all operating conditions of the tire/wheel assembly. Thesize of the individual material of the flowable material 40 must besmall enough that it can flow in an interior chamber 30 having arelatively small height. Although not shown, it is contemplated that theflowable material may include an optional lubricating agent such as talcor graphite which may help the material enhance and/or retain itsflowable characteristics.

The amount of flowable material 40 within the balance weight 10 shouldbe sufficient to enable the balance weight 10 to balance the tire/wheelassembly. In use, the balance weight 10 is preferably applied in thesame manner as a standard lead balance weight using a spin balancemachine. The tire/wheel assembly is mounted on the spin balancer and theout of balance condition is detected. The spin balancer recommends anamount of weight to be positioned at a particular circumferentialposition and at a particular predetermined distance from the axis in oneor more predetermined planes. When using balance weight 10 of thepresent invention, the total weight of the balance weight 10 (includingthe cartridge 20 and flowable material 40) should be equivalent to theamount of weight called for by the balance machine. Therefore the arclength of the cartridge 20 and the amount of flowable media 40 will beproportional to the specified weight with larger imbalances requiring alarger cartridge arc length and more flowable media 40, and vise versa.It is generally contemplated that the amount of flowable material 40used in a cartridge 20 will vary between 5 to 95 percent of the volumeof the internal chamber 30. In one embodiment of the invention, theamount of flowable material 40 as shown is approximately two-thirds ofthe volume of the internal chamber 30, which has been shown to provideoptimized dynamic balancing during current testing, however any amountsufficient to allow the flowable material to sufficiently move andbalance the tire/wheel assembly is contemplated. In some applicationswhere the lead balance weight is merely replaced, the entire volume ofthe interior chamber can be filled with material 40 such that thebalance weight 10 acts as a fixed weight.

The prior art lead balance weights are fixed in position by an operatoras directed by the spin balance machine. The lead balance weights may beattached to the wheel slightly off position by the operator. Thisrequires the operator to rebalance. Additionally, once the tire/wheelassembly is in operation on the vehicle, tire wear, pot holes, etc. willcause the tire/wheel assembly to go out of balance. In contrast, thebalance weight 10 of the present invention allows the weight of theflowable media 40 to move circumferentially as well as laterally withinthe cartridge 20. The operator attempts to center the balance weight 10of the present invention at the location specified by the spin balancemachine. If the operator misses the exact location slightly, theflowable media 40 is able to adjust the effective balance location ofthe tire/wheel assembly by moving within the cartridge 20 to obtain abalance equilibrium. Accordingly, the balance weight operator need notbe as accurate, and the tire/wheel assembly stays in balance even duringoperation of the tire/wheel assembly as the balance location moves alongthe wheel. It is also contemplated that more than one balance weight 10may be used in the present invention—just as with the prior art leadbalance weights.

Referring now to FIG. 5, an embodiment of the balance weight 10 is shownattached to a wheel 50 of a tire/wheel assembly 60 by an adhesive 70. Aspreviously mentioned, the trend toward the more aesthetic aluminum alloywheels makes it important that the weight is not visible. Accordingly,one possible placement is that the weight 10 may be attached on theinboard side of the spider 52 along the brake side of the tube well 54of the wheel 50. The weight 10 may be attached to the tube well 54 usingan adhesive 70 similar to that used by tape weights. As used in thisembodiment, the balance weights 10 are preferably pre-manufactured todifferent lengths, or arc lengths, of varying total weights. The balanceweight 10 is applied in the same manner as are the tape weights asinstructed by the particular balance weight machine (not shown). Whenattaching weights to the brake side of the tube well 54, some operatorswill often use single plane balancing using the tire/wheel assemblycenterline as “good enough”, however most newer balancing machines canstill utilize dual plane balancing by providing dual planes along thesurface of the brake side of the tube well 54. Direct measure balanceweight placement and 360 degree weight placement display capabilitiesmake positioning balance weight 10 both simple and accurate to balancethe tire/wheel assembly 60.

Referring now to FIG. 6, an embodiment of the balance weight 10 is shownattached to an inboard side flange 56 of the wheel 50 of the tire/wheelassembly (not shown) by an adhesive 70. The cartridge 20 is shown havingphysical dimensions which corresponds to that of the mating surface ofthe flange 56. In this manner, the balance weight 10 is positionedsimilar to that of the prior art balancing rings, except that thebalance weight has a limited arc length that enables faster balancingand prevents a severe out of balance condition at slower speeds as isinherent with the prior art balancing rings.

Referring now to FIG. 7, an embodiment of the balance weight 10 is shownattached to an inboard side flange 56 of the wheel 50 by a clip 80. Theclip 80 is formed similar to the standard prior art lead balance weightclips and attaches balance weight 10 to a flange 56 of the wheel 50.

While the balance weight 10 is typically used on the wheel of anassembled tire and wheel, the balance weight can also be used prior toassembly of the tire and wheel. In this method the tire and wheel areindividually balanced typically using a bubble balancer and the two arebalance matched for minimizing imbalance. The balance weight is thenattached to the wheel or the tire. This method is particularly usefulwhen attaching the balance weight to the inner liner of the tire or thepressure side of the wheel tube well.

Another variation of this balancing method involves the use of aplurality of balance weights 10 positioned adjacent to each, and end toend, about either the wheel or tire such that the entire 360 degreecircumference of the wheel or tire is covered by the plurality ofbalance weights 10. For example, two generally 180 degree balanceweights would be positioned in a radial plane circumferentially aboutthe tire or wheel and the two balance weights 10 would work together tocounter any imbalance.

Another benefit of the present invention is that the flowable media 40in the balance weight 10 has the ability to help dampen minor vibrationof the tire/wheel assembly due to various causes such as tire uniformityproblems. This helps promote a smoother ride for the occupants of thevehicle.

It is also contemplated that balance weight 10 could be mounted on theinterior or tire side of the tube well. However, this placement willrequire knowledge of the heavy spot location of the wheel 50 and tire 60such that the balance weight 10 will be properly positioned in alocation to compensate the imbalance of the assembled and inflatedtire/wheel assembly.

Other applications of the cartridge style balance weight include aversion that is fabricated directly into the tire 60 or wheel 50 as bestshown in FIGS. 8 and 9. In this instance, the cartridge 10 may be formedas a cavity in the wheel 50 with flowable material captured in thecavity or attached to the wheel 50 during the manufacturing process. Thecartridge 10 may also be formed as part of the inner liner of the tire60, positioned below the inner liner, or directly attached to the innerliner during the manufacturing of the tire 60. The use of the balanceweight cartridge 10 in manufacturing is fully contemplated in thepresent invention and the claims should be construed to include theseembodiments without limitation.

While this invention has been described with reference to preferredembodiments thereof, it shall be understood that such description is byway of illustration and not by way of limitation. Accordingly, the scopeand content of the present invention are to be defined only by the termsof the appended claims.

1. A balance weight for a tire/wheel assembly comprising: a cartridgecomprising an interior chamber at least partially filled with a flowablebalance media; and an adhesive means for attaching the cartridge to thetire/wheel assembly; wherein the cartridge is longitudinally arcuate, atleast when attached to the tire/wheel assembly, about an angle of 180degrees or less; wherein the cartridge is attached to a non-pressurizedside of the tubewell of the tire/wheel assembly or a rim flange of thetire/wheel assembly.
 2. The balance weight of claim 1, wherein theflowable media occupies between 5 and 95 percent of the volume of theinterior chamber.
 3. The balance weight of claim 1, wherein the flowablemedia occupies the entire volume of the interior chamber.
 4. The balanceweight of claim 1, wherein the flowable media is at least partiallycomprised of a material selected from the group consisting of ferrousmetals, non-ferrous metals, ceramics, plastics, glass, alumina, andpolymers.
 5. The balance weight of claim 1, wherein the flowable mediais at least partially comprised of a form selected from the groupconsisting of particulates, spheres, powder, shot, and beads.
 6. Thebalance weight of claim 1, wherein the flowable media is at leastpartially comprised of a liquid.
 7. The balance weight of claim 1,wherein the cartridge is manufactured of a polymeric material or ametallic material.
 8. The balance weight of claim 1, wherein thecartridge is manufactured as an extrusion, molded, or fabricated.
 9. Thebalance weight of claim 1, wherein the cartridge has a cross-sectionalgeometry in the form generally of a “D”, an oval, square, or arectangle.
 10. The balance weight of claim 1, wherein the cartridge islongitudinally arcuate about an angle of about 90 degrees or less. 11.The balance weight of claim 1, wherein the cartridge is longitudinallyarcuate about an angle of about 15 degrees–45 degrees.
 12. The balanceweight of claim 1, wherein the cartridge comprises a plurality ofinterior chambers.
 13. The balance weight of claim 1, wherein theflowable media dampens vibration of the tire/wheel assembly.
 14. Amethod of balancing a tire/wheel assembly comprising the steps of:providing a tire/wheel assembly; determining a weight amount of animbalance of the tire/wheel assembly and a location to correct theimbalance of the tire/wheel assembly using a tire/wheel assemblybalancing equipment; providing at least one balance weight comprising acartridge comprising an interior chamber at least partially filled witha flowable balance media, wherein the cartridge is longitudinallyarcuate, at least when attached to the tire/wheel assembly, about anangle of 180 degrees or less; and attaching the at least one balanceweight to a non-pressurized side of the tubewell of the tire/wheelassembly or a rim flange of the tire/wheel assembly at the location tocorrect the imbalance of the tire/wheel assembly.
 15. The method ofclaim 14, wherein the step of determining a weight amount of animbalance of the tire/wheel assembly and a location to correct theimbalance of the tire/wheel assembly using a tire/wheel assemblybalancing is accomplished by using a spin balance machine or a bubblebalancer.
 16. The method of claim 14 further comprising a step ofverifying that the tire/wheel assembly is balanced by using a tire/wheelassembly balancing equipment.
 17. The method of claim 14, wherein thestep of providing at least one balance weight is accomplished in part byselecting a balance weight from a plurality of balance weights ofdifferent weights such that the weight of the selected balance weightmatches the amount of weight imbalance of the tire/wheel assembly.
 18. Amethod of balancing a tire/wheel assembly comprising the steps of:providing a tire/wheel assembly; determining a weight amount of animbalance of the tire/wheel assembly and a location to correct theimbalance of the tire/wheel assembly using a tire/wheel assembly balanceequipment; providing at least one balance weight corresponding to theweight of the amount of the imbalance of the tire/wheel assembly, the atleast one balance weight comprising a cartridge comprising an interiorchamber at least partially filled with a flowable balance media, whereinthe cartridge is longitudinally arcuate, at least when attached to thetire/wheel assembly, about an angle of 180 degrees or less; andadhesively attaching the at least one balance weight to anon-pressurized side of the tubewell of the tire/wheel assembly at thedetermined location to correct the imbalance of the tire/wheel assemblysuch that the tire/wheel assembly is balanced.
 19. The method of claim18 further comprising the step of verifying that the tire/wheel assemblyis balanced by using the tire/wheel assembly balance equipment.